A Shaykh by the name of Abu Ja'ar has said:  Our belief concerning them (thalimun) is that they are accursed [145] and dissociation from them is necessary.  Allah the Mighty and Glorious says; "For evil-doers there will be no helpers" [2,270;3,192;5,72].  And Allah says, Exalted is He: "Who doeth greater wrong than he who inventeth a lie concerning Allah?  Such will be brought before their Lord and witnesses will say:  These are they who lied concerning their Lord.  Behold!  The curse of Allah is upon the wrong-doers, who debar (men) from the way of Allah, and would have it crooked, and who are disbelievers in the Hereafter"  [11,18-19]. Ibn Abbas in explaining this verse says:  Verily, in this context, by "the way of Allah" (sabil Allah) is meant Ali bin Abi Talib and the Imams, on whom be peace.
 And in the book of Allah (are mentioned) two kinds of leaders: he who guides rightly and he who leads astray.  And Allah the Exalted says:  "And We made them chiefs (or leaders) who guide by Our command" [21,73;cp.32,24]. And Allah says:  "And We made them patterns that invite unto the Fire, and on the Day of Resurrection they will not be helped.  And We made a curse to follow them in this world and on the Day of Resurrection they will be among the hateful" [28,41-42].
 

 Now when the following verse was revealed:  "And guard yourselves against a chastisement which cannot fall exclusively on those of you who are wrong-doers" [8,25], the Prophet (s.a.w.) said: He who will wrong Ali as regards my successor after my death, it is as though he has denied my apostleship and the apostleship of (all) the prophet before me, on whom be peace.  And he who befriends the wrong-doers is himself a wrong-doer."
 

Allah the Mighty and Glorious says:  "O ye who believe!  Choose not your fathers, nor your brethren for friends if they prefer disbelief to faith.  Who so of you taketh them for friends, such are wrong-doers"[9,23].  And He the Mighty and Glorious has said:  "O ye who believe!  Be not friendly with a folk with whom Allah is wroth, (a folk) who have despaired of the Hereafter as [146] the disbelievers despair of those who are in the graves" [60,13].  And He the Mighty and Glorious says:  "Thou wilt not find folk who believe in Allah and the Last Day loving those who oppose Allah and His Messenger, even though they be their fathers or their sons or their brethren or their clan.  As for such, He hath written faith upon their hearts. . ." [58,22].  And He says, Exalted is He:  "He among you who taketh them for friends is (one) of them.  Lo! Allah guideth not wrong-doing folk" [5,51].  And the Mighty and Glorious says:  "And incline not toward those who do wrong lest the fire touch you" [11,113].
 

 (The literal meaning of ) thulm is the placing of a thing at a place which is not its own.  So he who claims Imamat, not being an Imam, is an accursed wrong-doer (thalim).  And he who ascribes Imamat to those who are not entitled to it, he too is an accursed wrongdoer.
 And the Prophet (s.a.w.) said:  He, who denies Ali, his Imamat after me, verily denies my apostleship(nubuwwa).  And he who denies me apostleship, has denied Allah His divinity.
 And the Prophet, on whom be the blessings and mercy of Allah, said:  O Ali, you will be the wronged one (muthlum) after me; and he who wrongs you has verily wronged me; and he who acts justly towards you has verily acted justly towards me; and he who denies your (claim) has verily denied mine; and he who treats you as an enemy has verily treated me as an enemy; and he who obeys you has verily obeyed me; and he who disobeys you has verily disobeyed me.
 

Our belief concerning him, who denies the Imamat to the Prince of Believers Ali bin Abi Taleb (a.s.), and the Imams after him, is that he is the like of him who denies the apostleship of all the prophets, on whom be peace.  And our belief concerning him, who believes in (the Imamat of) the Prince of Believers and denies a single one of the Imams after him, is that he is in the same position as one who accepts all the prophets but denies the apostleship of our Prophet Muhammad (peace be upon him).  And [147] Imam Ja'far as-Sadiq (a.s.) said:  He who denies the least among us is like him who denies (the claims of) the first among us.
 And Imam Ja'far as-Sadiq (a.s.) said:  He who doubts in the infidelity (kufr) of our enemies who have wronged us is himself an infidel (kafir).
 

 The Prince of Believers (a.s.) said: "Ever since I was born I have always been wronged."  When Aqil used to suffer from ophthalmia (ramad), he used to say:  Do not sprinkle eye-powder into my eyes, until you sprinkle it into Ali's, and they would do so although I had no ophthalmia.
 And our belief concerning him who fought Ali is that he was an unbeliever (kafir), on account of the saying of the Prophet, on whom be the blessings and peace of Allah:  "He, who fought me; and he, who waged war on Ali, waged war on me; and he, who waged war on me, did so against Allah."  And (also) on account of his (Prophet's) saying to Ali and Fatima and Hassan and Husayn, peace on all of them:  "I am the enemy of those who wage war against you, and at peace with those who are at peace with you."
 And as for Fatima, the blessings of Allah and His peace be on her, our belief is that she is the leader of the women of the world, both the earlier and the later ones.  And verily Allah the Mighty and Glorious is wroth with him who evokes her anger, and is well-pleased with him who pleases her, for He has weaned her and those who revere her from the Fire.  And she left the world displeased with those who had wronged her and usurped her rights, and denied her the inheritance left by her father.  The Prophet (s.a.w.) said:  "Verily, Fatima is part of myself; he who angers her has angered me, and he who gladdens her [148] has gladdened me."  And the Prophet (s.a.w.) said:  "Verily Fatima is part of myself, and she is my spirit (ruh) which is between my two flanks.  What displeases her displeases me, and what gladdens her gladdens me."
 

Our belief is that absolution is necessary in respect of the four idols (awthan) - Yaghuth, Ya'uq, Nusr, and Hubal, and the four (female) idols (andad)-al-lat, Uzza, Manat, and Shi'ra; also in respect of those who worship them, and all their partisans and followers.  Verily these are the worst of Allah's creatures, and the declaration (of belief in) Allah and His Messenger (s.a.w.) and of the Infallible Imams (a.s.) does not become complete without seeking absolution as regards their enemies.
 

Our belief regarding those who killed the Prophets (s.a.w.) and the Infallible Imams (a.s.) is that they are unbelievers (kuffar) and polytheists (mushrikun), who will forever remain in the lowest stage of the Fire.

This Information was extracted from:
 1.  Ash-Shaykh As-Sadiq.  A Shi’ite Creed.  Published by the World Organization for Islamic Services.  Tehran, Iran, 1982.